Microwave amplitude-phase controller and method of controlling amplitude and/or phase of microwave

1. A microwave amplitude-phase controller comprising: a first substrate and a second substrate opposite to each other; a liquid crystal layer between the first substrate and the second substrate; a conductive layer on a side of the first substrate facing the liquid crystal layer, the conductive layer being configured to receive a first voltage signal; and a resonant structure on a side of the second substrate facing the liquid crystal layer, the resonant structure being configured to receive a second voltage signal and to transmit a microwave signal, wherein the resonant structure comprises: a capacitor comprising two electrodes opposite to each other, the two electrodes being respectively located at both ends of the capacitor and being on the side of the second substrate facing the liquid crystal layer; a bridged conductive structure in parallel with the capacitor, both ends of the bridged conductive structure being connected to the two electrodes of the capacitor, respectively; and a first signal line and a second signal line respectively electrically connected to the two electrodes of the capacitor, the first signal line being configured to receive a microwave signal to be modulated, and the second signal being configured to output a modulated microwave signal.

2. The microwave amplitude-phase controller according to claim 1 further comprising: a first alignment film between the conductive layer and the liquid crystal layer; and a second alignment film between the resonant structure and the liquid crystal layer.

3. The microwave amplitude-phase controller according to claim 2 , wherein the first alignment film and the second alignment film have the same alignment direction.

4. The microwave amplitude-phase controller according to claim 1 , wherein the capacitor comprises a first conductive strip and a second conductive strip which are opposite and parallel to each other, and spaced apart from each other, the first conductive strip and the second conductive strip having equal length and equal width, and wherein the bridged conductive structure comprises a third conductive strip which is axisymmetric, the third conductive strip having an axis of symmetry parallel to both the first conductive strip and the second conductive strip.

5. The microwave amplitude-phase controller according to claim 4 , wherein the resonant structure further comprises a first connecting line and a second connecting line, the first conductive strip is electrically connect to the first signal line and one end of the bridged conductive structure through the first connecting line, and the second conductive strip is electrically connected to the second signal line and the other end of the bridged conductive structure through the second connecting line.

6. The microwave amplitude-phase controller according to claim 5 , wherein the first conductive strip and the second conductive strip are both elongated and are perpendicular to the first connecting line and the second connecting line, respectively.

7. The microwave amplitude-phase controller according to claim 6 , wherein a gap between the first conductive strip and the second first conductive strip has a width less than or equal to 0.5λ, wherein λ is an operating wavelength of a microwave to be modulated.

8. The microwave amplitude-phase controller according to claim 4 , wherein the first conductive strip and second conductive strip are symmetrically arranged with respect to the axis of symmetry of the third conductive strip.

9. The microwave amplitude-phase controller according to claim 4 , wherein a length of the third conductive strip is less than or equal to 1λ, wherein λ is an operating wavelength of a microwave to be modulated.

10. The microwave amplitude-phase controller according to claim 4 , wherein the first conductive strip and the second conductive strip have a length less than or equal to 0.5λ and a width less than or equal to 0.5λ, wherein λ is an operating wavelength of a microwave to be modulated.

11. The microwave amplitude-phase controller according to claim 1 , wherein the capacitor comprises two interdigitated electrodes which are opposite to each other and spaced apart from each other.

12. The microwave amplitude-phase controller according to claim 1 , wherein an orthographic projection of the liquid crystal layer on the first substrate at least covers an orthographic projection of the capacitor on the first substrate.

13. The microwave amplitude-phase controller according to claim 1 , wherein a thickness of the liquid crystal layer is less than or equal to 0.5λ, wherein λ is an operating wavelength of a microwave to be modulated.

14. The microwave amplitude-phase controller according to claim 1 , further comprising: a frame between the first substrate and the second substrate, wherein the frame, the first substrate and the second substrate enclose a cavity, the liquid crystal layer being filled in the cavity.

15. The microwave amplitude-phase controller according to claim 1 , wherein the conductive layer is grounded.

16. A method of controlling amplitude and phase of a microwave by using the microwave amplitude-phase controller according to claim 1 , comprising: applying the first voltage signal to the conductive layer of the microwave amplitude-phase controller, and applying the second voltage signal to the resonant structure of the microwave amplitude-phase controller; and inputting a microwave signal to be modulated to the resonant structure of the microwave amplitude-phase controller, and adjusting a voltage difference between the first voltage signal and the second voltage signal until a modulated microwave signal output by the resonant structure has required amplitude and phase.